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The Handbook: Prevention and Control of Wildlife Damage Management, Internet Center Wildlife Damage for

July 1994

Kangaroo

Volney W. Howard Jr. New Mexico State University

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Howard, Volney W. Jr., " Rats" (1994). The Handbook: Prevention and Control of Wildlife Damage. 22. https://digitalcommons.unl.edu/icwdmhandbook/22

This Article is brought to you for free and open access by the Wildlife Damage Management, Internet Center for at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in The Handbook: Prevention and Control of Wildlife Damage by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Volney W. Howard, Jr. Professor of Wildlife Science Department of Fishery and KANGAROO RATS Wildlife Sciences New Mexico State University Las Cruces, New Mexico 88003

Fig. 1. The Ord’s kangaroo , Dipodomys ordi

Identification and Range Fumigants Damage Prevention and There are 23 of kangaroo rats Control Methods Aluminum phosphide and gas car- (genus Dipodomys) in . tridges are registered for various Fourteen species occur in the lower 48 Exclusion burrowing . states. The Ord’s (D. ordi, Fig. 1) occurs in 17 US states, Canada, Rat-proof fences may be practical only Trapping and Mexico. Other widespread species for small areas of high-value crops. Live traps. include the Merriam kangaroo rat Cultural Methods Snap traps. (D. merriami), bannertail kangaroo rat (D. spectabilis), kangaroo rat Plant less palatable crops along field Other Methods (D. deserti), and kangaroo edges and encourage dense stands rat (D. microps). of rangeland grass. Use water to flush kangaroo rats from . Repellents Kangaroo rats are distinctive rodents with small forelegs; long, powerful None are registered. hind legs; long, tufted tails; and a pair Toxicants of external, fur-lined cheek pouches similar to those of pocket gophers. Zinc phosphide. They vary from pale cinnamon buff to a dark gray on the back with pure white underparts and dark markings

PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994 Cooperative Extension Division Institute of Agriculture and Natural Resources University of Nebraska - Lincoln United States Department of Agriculture and Plant Health Inspection Service Animal Damage Control B-101 Great Plains Agricultural Council Wildlife Committee their burrows for storage. This caching entrances with soil during the day to activity can cause significant impact on maintain a more constant temperature rangeland and cropland. They remove and relative humidity. They are often seeds from a large area, thus prevent- seen on roads at night, hopping in ing germination of plants, particularly front of headlights in areas where they grasses, in succeeding years. Since occur. these rodents do not hibernate, the Kangaroo rats often occur in aggrega- seed caches are a source of food dur- tions or colonies, but there appears to ing severe winter storms or unusually be little if any social organization hot summer weather. Kangaroo rats among them. Burrows are spaced to are quite sensitive to extremes in tem- allow for adequate food sources within perature and during inclement normal travel distances. Spacing of weather may remain underground for mounds will vary according to abun- several days. dance of food, but well-defined travel Fig. 2. Distribution of Ord’s kangaroo rats in lanes have been observed between North America. General , neighboring mounds. Reproduction, and When kangaroo rats are locally abun- on the face and tail. The largest, the dant, their mounds, openings, (D. ingens), has a Behavior and trails in vegetation and sand are head and body about 6 inches (15 cm) conspicuous features of the terrain. long with a tail about 8 inches (20 cm) Kangaroo rats breed from February to Both the number of burrows and indi- long. The bannertail kangaroo rat is October in southern desert states. The viduals per acre (ha) can vary greatly approximately the same size, but has a breeding period is shorter in the north- depending on locality and time of white-tipped tail. The other common ern states. The gestation period is ap- year. There are usually many more species of kangaroo rats are smaller. proximately 30 days. Reproductive burrow openings than there are rats. The Ord’s kangaroo rat has a head and rates vary according to species, food Each active burrow system, however, body about 4 inches (10 cm) long and a availability, and density of will contain at least one adult rat. tail about 7 inches (18 cm) long. populations. Females have 1 to 3 litters of 1 to 6 young per year. The young There could be as many as 35 rats per are born hairless and blind in a fur- acre (14/ha) in farmlands. In range- Habitat lined nest within the tunnel system. lands, 10 to 12 rats per acre (4 to 5/ha) Usually, the young remain in the nest is more likely. Kangaroo rats do not Kangaroo rats inhabit semiarid and and tunnel for nearly a month before have large home ranges; their radius of arid regions throughout most of the appearing aboveground. activity is commonly 200 to 300 feet (60 western and plains states. The Ord’s to 90 m), rarely exceeding 600 feet (183 Only a few females will breed after a kangaroo rat is the most common and m). They may move nearly a mile (1.6 prolonged drought when food is in widespread of the kangaroo rats (Fig. km) to establish a new home range. short supply. Most females will bear 2). Several other species are located in young when food is abundant, and Mexico, , and the southwest- some young females born early in the Damage and Damage ern United States. They generally are season will also produce litters before not found in irrigated pastures or Identification the season ends. crops, but may be found adjacent to these areas on native rangelands, espe- All kangaroo rats build tunnels in Historically, kangaroo rats were con- cially on sandy or soft soils. They also sandy or soft soil. The tunnel system is sidered to be of relatively minor eco- invade croplands under minimum till- fairly intricate, and consists of several nomic importance. They have come age in these areas, particularly areas sleeping, living, and food storage into direct conflict with human inter- under dry farming. chambers. The extensive burrowing re- ests, however, with large-scale devel- sults in a fair amount of soil being opment of sandy soil areas for brought up and mounded on the sprinkler-irrigated corn and alfalfa Food Habits ground surface. These mounds can be production. A primary conflict devel- mistaken for prairie dog mounds, par- ops at planting time when kangaroo Kangaroo rats are primarily seed eat- ticularly when observed on aerial rats dig up newly planted seeds and ers, but occasionally they will eat the photographs. They may vary in size clip off new sprouts at their base. vegetative parts of plants. At certain but can be as large as 15 feet (4.5 m) Damage is more severe when popula- times of the year they may eat insects. across and up to 2 feet (60 cm) high. tion densities are high. Smaller popula- They have a strong hoarding habit and tions apparently are able to subsist on will gather large numbers of seeds in Kangaroo rats are completely noctur- waste grain and damage is not as their cheek pouches and take them to nal and often plug their burrow apparent. Since kangaroo rats are

B-102 primarily seed eaters, they find irri- excluded by 1/2-inch (1.3-cm) mesh geous because it is thought to present gated fields and pastures a veritable hardware cloth, 30 to 36 inches (75 to little or no hazard of secondary poi- oasis and feed extensively on waste 90 cm) high. The bottom 6 inches (15 soning to small canids and a low haz- grain after harvest. cm) should be turned outward and ard to other nontarget wildlife. buried at least 12 inches (30 cm) in the Kangaroo rats have foiled attempts to Carefully read and follow all label ground. Exclusion may be practical for restore overused rangelands. Their instructions. Zinc phosphide is a small areas of high-value crops, such habit of collecting and caching large Restricted Use Pesticide for retail sale as gardens, but is impractical and too numbers of grass seeds restricts the to and use by certified applicators or expensive for larger acreages. natural reseeding process. In semiarid persons under their direct supervision, rangelands, activities of kangaroo rats Cultural Methods and only for those uses covered by the can prevent an area from making any applicator’s certification. appreciable recovery even though the Alfalfa, corn, sorghum, and other area received complete rest from live- grains are the most likely crops to be Fumigants damaged by kangaroo rats. When pos- stock grazing for 5 years or more. There are no fumigants registered spe- sible, planting should be done in early Reducing livestock grazing is not cifically for kangaroo rats. Aluminum spring before kangaroo rats become enough. As long as kangaroo rats phosphide and gas cartridges are cur- active to prevent loss of seeds. Less remain in an area, they will restrict the rently registered for “burrowing palatable crops should be planted reestablishment of desirable forages, rodents such as woodchucks, prairie along field edges that are near areas particularly native grasses. dogs, gophers, and ground squirrels.” infested with kangaroo rats. Legal Status High kangaroo rat numbers most often Trapping occur on rangelands that have been Live Traps. Trapping with box-type Most kangaroo rats are considered subjected to overuse by livestock. nongame and are not pro- (wire cage) traps can be successful in a Kangaroo rats usually are not abun- small area when a small number of tected by state game laws. Certain dant where rangelands have a good local subspecies may be protected by kangaroo rats are causing problems. grass cover, since many of the forbs These traps can be baited successfully regulations regarding threatened and that provide seeds for food are not endangered species. Consult local au- with various grains, oatmeal, oatmeal abundant in dense stands of grass. and peanut butter, and other baits. thorities to determine their legal status Thus, changes in grazing practices before applying controls. One problem is the disposal of kanga- accompanied by control programs roo rats after they have been trapped. Attention!! Five kangaroo rat species may be necessary for substantial, long- They usually die from exposure if they currently are listed as endangered by term relief. remain in the trap for over 6 hours. If the US Fish and Wildlife Service. They the rats are released, they should be Repellents are found mostly in California and taken to an area more than 1 mile (1.6 include the Fresno kangaroo rat (D. There are no registered repellents for km) from the problem site. The release nitratoides exilis), giant kangaroo rat kangaroo rats. site should provide suitable habitat (D. ingens), Morro Bay kangaroo rat and be acceptable to everyone (D. heermanni morroensis), Stephens’ Toxicants involved. Do not release kangaroo rats kangaroo rat (D. stephensi including Zinc Phosphide. At present, 2% zinc in areas where landowners do not D. cascus), and phosphide bait is federally registered want them. (D. nitratoides nitratoides). Persons for the control of the bannertail, Mer- Snap Traps. working in California, southern Ore- Trapping with snap riam, and Ord’s kangaroo rats in gon, south central Nevada, and west- traps is probably the most efficient and rangeland vegetation and noncrop ar- ern Arizona should have expertise in humane method for kangaroo rats. eas. Some states may also have Special identifying these species, their Mouse traps will suffice for smaller Local Needs 24(c) registrations for zinc mounds, and the ranges in which they animals, but Victor® “museum spe- phosphide baits to control kangaroo likely occur. cials” or rat traps are needed for larger rats. kangaroo rats, particularly the Damage Prevention and Zinc phosphide pelleted rodent bait bannertail. Successful baits include whole kernel corn, peanut butter and Control was tested on kangaroo rats in New Mexico (Howard and Bodenchuk oatmeal, and oatmeal paste, which are placed on the trigger mechanism. Place Exclusion 1984). Levels of control were much lower than those for 0.5% strychnine traps near, but not inside, the burrow Exclusion is most often accomplished oats, but higher than for 0.16% strych- entrances or along runways between by the construction of rat-proof fences nine oats. Zinc phosphide applied in mounds. Check traps each day to and gates around the area to be pro- June produced the highest percentage remove dead kangaroo rats. Reset tected. Most kangaroo rats can be of control. Zinc phosphide is advanta- tripped traps and replace baits that

B-103 may have been removed by ants or either species were denser. This forage Information on specific control tech- other insects. Do not use whole kernel loss (3 Animal Unit Months [AUMs]) niques and limitations can be obtained corn when large numbers of seed- is currently valued at $6 to $12 per sec- from your local extension agent or eating songbirds are in the area. tion in New Mexico. extension wildlife specialist. In addi- tion, personnel from state wildlife Bannertail kangaroo rats stored 2.9 Other Methods agencies or USDA-APHIS-ADC can tons (2.6 mt) of plant material per sec- provide information on control If kangaroo rats from only one or two tion per year in their burrows. Fur- measures available in your area. mounds are causing the problems, and thermore, production of grasses on water is available, they may be flushed rangelands in excellent condition were from their burrows and either killed or reduced by 10.6% (or 12 AUMs) by Acknowledgments allowed to go elsewhere. Collapse the denuding of areas in the vicinity of mounds after the kangaroo rats have kangaroo rat mounds. These estimates Figure 1 by Emily Oseas Routman. been driven out. This not only levels do not include the loss of regeneration Figure 2 adapted by the author from Burt and the surface but also allows you to of desirable grasses due to seed Grossenheider (1976). detect burrow reinvasion by other consumption. kangarooa rats. Use caution when flushing burrows with water or trap- In areas that are being farmed for pro- For Additional ping kangaroo rats. The burrow duction of pasture or commercial Information entrances are sometimes used by crops, densities of kangaroo rats could become much higher than those rattlesnakes seeking to escape heat and Burt, W. H., and R. P. Grossenheider. 1976. A direct sunlight during hot days. Even reported by Wood (1969). These higher field guide to the , 3d ed. on warm days, rattlesnakes may be densities, coupled with higher crop Houghton Mifflin Co., Boston, 289 pp. values, could conceivably produce found near mounds since kangaroo Eisenbert, J. F. 1963. The behavior of heteromyid rats are a source of food for them. losses greater than $100 per acre rodents. Univ. California Publ. Zool. ($250/ha). 69:1-100. The cost of controlling kangaroo rats Howard, V. W., Jr., and M. J. Bodenchuk. 1984. Economics of Damage Control of kangaroo rats with poison baits. can be quite high if labor-intensive New Mexico State Univ. Range Improv. Task and Control methods are employed. Of course, the Force. Res. Rep. 16. cost per mound will be higher when Wood, J. E. 1965. Response of rodent Wood (1969) found that Ord’s kanga- controlling a few mounds rather than populations to controls. J. Wildl. Manage. roo rats eat about 1,300 pounds (585 larger numbers. Trapping is the most 29:425-438. kg) of air-dried plant material per sec- costly method; toxicants the least Wood, J. E. 1969. Rodent populations and their tion per year in south central New costly. The cost of the traps varies impact on desert rangelands. New Mexico Mexico based on average (medium) greatly, depending on the size, num- Agric. Exper. Stn. Bull. 555. 17 pp. densities. He also reported an addi- ber, and kind of traps used. Live traps tional 336 pounds (151 kg) of air-dried cost more than snap traps. The cost of plant material per section per year con- toxic baits is relatively low on a per- sumed by bannertail kangaroo rats in mound basis. Labor costs are reduced Editors the same area under average when large areas are treated with toxic Scott E. Hygnstrom (medium) population densities. These grain baits using a four-wheel, all- Robert M. Timm Gary E. Larson data were for arid rangelands and terrain cycle. could be higher if the populations of

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